Control apparatus



June 14, 1949. M. GoT'rLlEB ETAL CONTROL APPARATUS Filed June 26, 1945 INVENTORS MANlous GoT-mas 2 FRANK A. MEYER ATTORNEY WITNESSES: 4). fw. M 912/.

. the generator with respect to thev motor.

Patented June 14, 1949 UNITED STATES ?ATENT OFFICE CONTROL APPARATUS Application June 26, 1945, Serial No. 601,672

(Cl. IS7- 158) 4 Claims. l

The invention relates' to a turbine or prime mover having elastic'v fluid, hereinafter referred to as steam-,. admitted theretounder control of a speed governor operating the admission valve and it has for anv object to provide manuallyoperable means for limiting, in a variable' manner, the extent of. opening` of. the admission valve and, therefore, the flow of steam: to the turbine or prime mover.

Wherev a turbine is.- connected toa ships propeller by an. electric drive,A operatingl conditions may occur: making. it desirable to limit the admission. of. steam; to limit the.: turbine torque. to avoid interruption of the drive, or pullfout of To accomplish this resultgwe provide a turbine: having its admission valve operated, by aservo--motor Whose relay is controlled by a speed-responsive governor together with meansw-hich is' manually operable to adjust, in a variable manner; the extent of Operation of the servo-motor to limit opening of the admission valve to restrict the ovv of steam to a desired extent, the governor and the servo-motor remaining eiective at all times to move the admission valvein a closing direction to avoid excessive speeds of thefturbine. The manuualy-operableY means has one position in which it is entirely free of the servo-motor so that theV admission valve is wholly under con trol of the speed governor and such means is movable away from that positionto limit, to the extent of such movement, operation of the servomotor to move the admission valve in an opening direction, the servo-motor remaining free for operation to move the valve inl a closing direction. Therefore, the improved governingy mechanism may be operated for complete control of the turbine in response tospeedor it mayv be adjusted soI asto limitV the. flow of steam to the turbine to a desired extent independently of speedA responsewhile, at. the` same' time, preserving full speed-responsive controlv to restrict the flow of steam so as to avoid over-speeding. Therefore, a further objectof the invention is to provide apparatusv of this character operating in the manner andfor the purposes stated.

These and other objects are eiected by the invention as will be` apparent from the following descriptiony and. claims. taken in. connection with the accompanying drawing, forming a part. of thi`s.application, in which:

The' figure is a fragmentary view, partly in elevation and partly in section, showing the improved governing mechanism.

In thedrawing, therev hewn a steaml turbine l 2 I0 provided with an admission valve II cooperating with a seat I2 to control the flow of steam thereto. The admission valve `is operated by servo-motor means, at I3, controlled by the governor, at It, operating in response to speed of the turbine.

The servo-motor means includes an operating piston I5 arranged in the cylinder I5 and motive fluid is admitted to and exhausted from the cylinder at opposite sides of the piston by means of the relay, at I8.

The relay is in the form of a piston valve I3 arranged in the valve cylinder 20. The piston valve has piston portions or lands 2l', 22/ and 23 which lap motive fluid supply and' exhaust ports 24, `25 and 26, respectively, when the relay'piston valve is in a neutral, mid, orl cut-off position. Motive uid is supplied to and exhausted from opposite endsof the cylinder by means of cylinder ports 21 and 28. While the ports 24 and 2B are shown as being pressure supply ports and the port 25 as an exhaust port, it will be obvious that the port arrangement might be reversed, motive liquid being supplied to the port 2,5 and being exhausted from the ports 24 and 26, provided that the valve-operatingv and follow-up linkages are modied suitably so as to preserve the mode of operation herein described.

The pressure ports 2li and 26 are supplied with oil from the line 29 in which pressure is maintained by the pump 30 driven by the turbine. The exhaust port 25Y has adrain or return line 3i.

The operating piston I5' has a rod. 32 pivotally connected, at 33, to a lever 34, which is fulcrumed, at 35, and is pivotally connected, at 363, to the valve rod 3i.

Follow-up mechanism, at 38', includes a lever 39 pivotally connected, at 40, to the piston rod 32, fulcrumed, at 4I, and pivotally connected, at 42', to the memberl 43 movable in the direction ofmovement of the relay piston valve I9. The follow-up member 43, therefore, has a iixedv ratio of movement with respect to movement of the operating piston.

A spring 44 is interposed between the followup member`43 and the adjacent end of the relay piston valve I9 and it exerts force on the latter to move it in a direction to connect the pressure port 26 with the cylinder port 2B for upward movement ofthe operating piston to move the valve II in an opening direction. As hereinaft described, the governor, at Iii, lis speed of the turbine to apply `force piston valvetomove iriad tio inder port 21, the other cylinder port 28 being placed in communication with the exhaust port 25, to effect downward movement of the operating piston l5 and movement of the valve Il in a closing direction. There is preferably also provided a spring engaging the lower end of the piston valve to exert force thereon in opposition to the force of the spring 44, the force of the spring 45 acting in the same direction as the speed-responsive force provided by the governor.

In operation, the relay piston valve I3 normally occupies a cut-olf or neutral position. If there is an increase in turbine load, the speed-responsive force diminishes, and, in consequence, the relay piston valve moves downwardly to place the pressure port 26 in communication with the cylinder port 28 for upward movement of the operating piston l5 and movement of the valve H in an opening direction to provide steam flow adequate for the increase in load; however, at the same time, the follow-up mechanism, at 38, is operated by movement of the piston l5 to reduce the load of the spring 44, the operating piston l5 continuing to move and the load of the spring 44 being continually reduced until the relay piston valve is restored to neutral or cut-oir position with the forces acting thereon in equilibrium. On the other hand, if there is a decrease in load, the preponderating governor force causes the relay piston valve to move upwardly to effect downward movement of the operating piston and movement of the admission valve in a. closing direction, and, as the operating piston moves downwardly, the follow-up mechanism increases the loading of the spring 44 and the force exerted thereby on the relay piston valve until the latter is restored to neutral position with the forces acting` thereon in equilibrium.

While any suitable governor may be used for applying a speed-responsive force to the relay, we prefer to employ one of the hydraulic type. Accordingly, the relay piston valve i9 cooperates with the cylinder 20 to present a piston area to the liquid pressure space 46 provided by the lower end of the valve cylinder and including a port 41. Liquid is supplied from the pressure line 29 through the orice 48 to the space 46.

The turbine rotor shaft 50 is connected by means of gearing 5l to the governor spindle 52 having its upper end provided with flyweights 53 with which cooperate the load spring 54 and the abutment 55 for the lower end of the stem 56 of the cup valve 51 arranged in covering relation with respect to the discharge end of the port 41 for the pressure space 46. An increase in turbine speed results in an increase in the upward force acting on the cup valve and due to centrifugal force of the fiyweights to cause the cup valve to move closer to its seat 58 bounding the discharge end of the port 41 to restrict the escape of oil from the space 46, in consequence of which such pressure increases until the force of such liquid pressure acting downwardly on the pressure area of the cup valve increases to balance the increased centrifugal force. On the other hand, if the turbine speed decreases, the centrifugal force is reduced and the cup valve moves slightly to increase the escape area from the pressure space, in consequence of which the liquid pressure in the latter space decreases, the decrease continuing until the change in liquid pressure force acting downwardly on the cup valve balances the change in centrifugal force. Thus, it will be seen, that each change in load and, therefore, in speed is accompanied by a length, the lever is pivotally connected at 61 to the depending link 68 whose lower end is engageable with the fixed abutment 10. A spring 66 biases the link toward the fixed abutment. The link has an abutment 64 which extends underneath the relay abutment 6 l The fulcrum 66 is movable through a range such that, at one extreme, the lever 65 clears the abutment and, at the other extreme, the lever overhangs the abutment and cooperates therewith to limit the maximum extent of opening of the admission valve. Movement of the fulcrum is eiected by the link 1| connected by the bellcran'k 12 to the link 13, which is pivotally connected to the lower end of the hand lever 14.

As shown, the hand lever 14 is near its extreme position A and the fulcrum 66 is positioned for limiting the extent of 'opening of the admission valve, the admission valve being prevented from opening wider because the lever and the link 68 cooperate with the follow-up member and relay abutments 66 and 6I to positively hold the relay against downward movement from neutral position for operation' of the operating piston to open the admission valve wider.

As the hand lever is moved from A toward B, the fulcrum 66 is lowered to increase the effective length of the linkage tie for the follow-up member and relay abutments in consequence of which, for neutral position of the relay, the extent of admission valve opening is increased until, at position B, the end 63 of the lever entirely clears the abutment 60 to provide for movement of the admission valve through its full range wholly in response to the governor.

Movement of the fulcrum 66 downwardly from the position shown causes the lever 65 to tilt about the follow-up member abutment 60 until the lower end of the link 68 engages the abutment 16, whereupon continued downward movement of the fulcrum produces tilting of the lever about the link pivotal connection 61 until, with the lever 14 at position B, the lever end 63 fully clears the roller abutment 60.

Assuming that the hand lever 14 is in position B and that it is moved toward A, the lever 65 tilts about the pivotal connection 61 until it engages the abutment 60, whereupon continued tilting occurs about the latter and the link 68 israised against the force of the spring 69 to engage the link abutment 64 with the relay abutment 6i.

If, after engagement of the abutments 64 and 6l, as just described, continued movement results in the relay being lifted from neutral position, the servo-motor is thereby rendered effective to move the admission valve in a closing direction and the follow-up member 43 moves downwardly to restore the relay to neutral position, the relay abutment 6| pulling down the link 68 to keep the overhanging lever end 63 engaged with the roller abutment 60.

With the fulcrum 66 in a position limiting lopening of the admission valve, the lever 65 is engagea positioned by the follow-up 'member43' soas to support the relay'inneutral position independently of action of the governor in response-'to increase in load tending to move the relay downwardly for wider opening of the admission valve; however, as the relay is free to move upwardly relative to the link, it remains subject to operation by the governor to move the admission valve in a closing direction in response to increase in speed pursuant to decrease in load..

From the apparatus described, it will be ap'- parent that We have devised a speed governor together with manually-controllable means cooperating therewith so that the turbine load may be limited to a desired extent, that the governor is at all times capable of moving the steam valve in a closing direction to limit the speed, and that the manually-controllable means forlimiting the load is adjustable through a range from a position where it has no effect upon the governor mechanism, the latter then having full control o the turbine, to a position such that the load is limited to a maximum extent.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modications without departing from the spirit thereof.

What is claimed is:

l. In mechanism for limiting the extent of opening of the admission valve of a prime mover to limit the flow of motive fluid thereto, an operating piston mechanically connected to the valve, a cylinder for the piston, a relay movable in opposite directions from neutral position to control H the admission and exhaust of motive fluid to and from the cylinder at opposite sides of the piston, follow-up mechanism including a member movable in the direction of movement of the relay and in xed relation to the operating piston and admission valve and a spring interposed between the follow-up member and the relay for exerting force on the latter, a governor responsive to speed of the prime mover for exerting force on the relay in opposed relation to that oithe i spring, means including the follow-up member to hold the relay in neutral position against movement in a direction for Wider opening of the admission valve while providing for movement thereof by the governor in the other direction to f move the admission valve in a closing direction, and manual means for adjusting the last-named means to vary the extent of maximum opening of the admission valve.

2. In mechanism for limiting the extent of opening of the admission valve of a prime mover to limit the flow of motive uid thereto, an operating piston mechanically connected to the valve, a cylinder for the piston, a relay movable in opposite directions from neutral position to control the admission and exhaust of motive fluid to and from the cylinder at opposite sides of the piston, follow-up mechanism including a member movable in the direction of movement of the relay and in xed relation to the operating piston and admission valve and a spring interposed between the follow-up member and the relay for exerting force on the latter, a governor responsive to speed of the prime mover for exerting force on the relay in opposed relation to that of the spring, abutments on the follow-up member and on the relay, linkage mechanism cooperating with the abutments so that the followup member positively supports the relay in neutral position against movement in a direction to 6. increase the extent of valve opening while providing for movement thereof by the governorin the other direction to eiect movement of the valvein a closing direction, and manual means for adjusting the linkage mechanism so that the admission valve is movable through its full range entirely in response to the governor or has its movement in an opening direction limited to a desired' extent.

3.1mA mechanism for limiting the extent of opening oithe admission valve of a prime mover tov limit the ilow of motive uid thereto, an operating piston mechanically connected to the valve; a cylinder for the piston; a relay movable in opposite directions from neutral position to control the admission and exhaust of motive fluid to and from the cylinder at opposite sides of the piston; follow-up mechanism including a member movable in the direction of movement of the relay and in fixed relation to the operating piston and admission valve and a spring interposed between the member and the relay for exerting force on the latter; a governor responsive to speed of the prime mover for exerting force on the relay in opposed relation to that of the spring; abutments provided on said follow-up member and on the relay; a lever having one end arranged to extend over the follow-up member abutment and engage the latter; a fulcrum for the other end of the lever; a link pivotally connected to the lever intermediately of the length of the latter and depending therefrom; a xed abutment engageable by the lower end of the link; an abutment on the link and engageable with the relay abutment underneath the latter; and manual means for moving the fulcrum, in one direction, to tilt the lever about the follow-up member abutment until the lower end of the link engages the fixed abutment and then about the link pivotal connection to move the overhanging end of the lever clear of the follow-up member abutment to provide for governor control of the admission valve over its entire movement range, and, in the other direction, to tilt the lever about the link pivotal connection until its overhanging end engages the follow-up member abutment and then about the latter to provide for the followup member supporting the relay in neutral position against movement in the direction for Wider opening of the admission valve.

4. In mechanism for limiting the extent of opening of the admission valve of a prime mover to limit the flow of motive iiuid thereto, an operating piston mechanically connected to the valve; a cylinder for the piston; a relay movable in opposite directions from neutral position to control the admission and exhaust of motive fluid to and from the cylinder at opposite sides of the piston; follow-up mechanism including a member movable in the direction of movement of the relay and in fixed relation to the operating piston and admission valve and a spring interposed between the member and the relay for exerting force on the latter; a governor responsive to speed of the prime mover for exerting force on the relay in opposed relation to that of the spring; abutments provided on the follow-up member and on the relay; a lever having one end arranged to extend over the follow-up member abutment and engage the latter; a fulcrum for the other end of the lever; a link pivotally connected to the lever intermediately of the length of the latter and depending therefrom; a fixed abutment engageable by the lower end of the link; a spring for biasing the link toward the fixed abutment; an abutment on the link and extending underneath the relay abutment; and manual means for moving the fulcrum, in one direction, to tilt the lever about the follow-up member abutment until the lower end of the link engages the fixed abutment and then about the link pivotal connection to move the overhanging end of the lever clear of the follow-up member abutment to provide for governor control of the admission Valve over its entire movement range, and, in the other direction, to tilt the lever about the link pivotal connection until its overhanging end engages the follow-up member abutment and then about the latter to provide for the follow-up member sup- REFERENCES CITED The following references are of record in the file'of this patent:

UNITED STATES PATENTS Name Date Pfau Jan. l2, 1937 Number 

